A Note on Noncommutative String theory and its low energy limit

The noncommutative string theory is described by embedding open string theory in a constant second rank antisymmetric $B_{\mu\nu}$ field and the noncommutative gauge theory is defined by a deformed $\star$ product. As a check, study of various scattering amplitudes in both noncommutative string and noncommutative gauge theory confirm that in the $\alpha^{'}\to 0$ limit, the noncommutative string theoretic amplitude goes over to the noncommutative gauge theoretic amplitude, and the couplings are related as $g_{YM}=G_0\sqrt{\frac{1}{2\alpha^{'}}}$. Furthermore we show that in this limit there will not be any correction to the gauge theoretic action because of absence of massive modes. We get sin/cos factors in the scattering amplitudes depending on the odd/even number of external photons.Comment: 14 pages including 2 figure

Changes in the electronic structure and properties of graphene induced by molecular charge-transfer

Interaction with electron donor and acceptor molecules such as aniline and nitrobenzene brings about marked changes in the Raman spectrum and the electronic structure of graphene, prepared by the exfoliation of graphitic oxide.Comment: 13 pages, 4 figure

Direct Simulation of Flow over A Wall-Mounted Hump

Simulating separated flows at high Reynolds numbers using Reynolds Averaged Navier-Stokes (RANS) modeled equations remains a challenge in aeronautics. The main hindrance to progress stems from the lack of extended de- tailed data pertinent to the root cause of failure of RANS models, as well as the little progress in RANS modeling innovations in the past several decades. The goal of the current effort is to generate data for separated flow at a Reynolds numbers where conventional models are challenged. We use Direct Numerical Simulations to model turbulent flow over the wall-mounted hump configuration to investigate the physics of flow separation and boundary layer recovery, as well as provide data relevant to the modeling community. A chord-based Reynolds number of Re(sub c) = 47,500 is considered with a turbulent inflow profile of Re(sub ) = 1,400 ( /c = 3%). We use FDL3DI, a code that solves the compressible Navier-Stokes equations using high-order compact-difference scheme and filter, with the standard re- cycling/rescaling method of generating turbulent boundary layers as inflow to the computational domain. Two differ- ent configurations of the upper-wall are analyzed for two sets of boundary conditions (slip and no-slip). The results are compared with the available higher Re(sub c) (= 936,000, Re(sub ) = 7,200, /c = 0.77%) experiment for major flow features. The simulated lower Rec allows for DNS-like mesh resolutions, and adequately wide spans. The results from these simulations show earlier separation and delayed reattachment compared to Re(sub c) = 936,000, and significantly higher skin friction in the forebody of the hump. We also find that the upper-wall shape and boundary condition influence pressure distribution over the hump, whereas skin friction is only influenced by the boundary condition

Study On Strength And Stress Strain Behaviour Of Self Curing Concrete

The concrete dilution process assumes a remarkable role in the construction of solid microstructure and pore structure. The idea of self-comfort is to reduce the water dissipation of the concrete and thus increase the water holding limit of the solid compared to normal cement. An unwise restoration can reduce the quality of the cement without too much stretching. It was found that the water soluble polymers used as additives in solid effects, the dilution quality characteristics of hard cement take a prominent role in the construction of a compact solid structure and thus improve its rigidity and workmanship. The quality of compression does not decrease with the use of SAP in self-healing concretes. The excision flexibility with SAP is not reduced in self-curing concrete. SAP can be used up to 0.6% of the bond weight without changing the different quality of the cement

Implicit Large-Eddy Simulations of Zero-Pressure Gradient, Turbulent Boundary Layer

A set of direct simulations of zero-pressure gradient, turbulent boundary layer flows are conducted using various span widths (62-630 wall units), to document their influence on the generated turbulence. The FDL3DI code that solves compressible Navier-Stokes equations using high-order compact-difference scheme and filter, with the standard recycling/rescaling method of turbulence generation, is used. Results are analyzed at two different Re values (500 and 1,400), and compared with spectral DNS data. They show that a minimum span width is required for the mere initiation of numerical turbulence. Narrower domains ((is) less than 100 w.u.) result in relaminarization. Wider spans ((is) greater than 600 w.u.) are required for the turbulent statistics to match reference DNS. The upper-wall boundary condition for this setup spawns marginal deviations in the mean velocity and Reynolds stress profiles, particularly in the buffer region

Resonant Raman of OH/OD vibrations and photoluminescence studies in LiTaO3 thin film

Resonant Raman spectra (RRS) of O-H and O-D vibration and libration modes, their combinations and higher harmonics have been observed in LiTaO3 polycrystalline thin films. RRS peaks are superimposed on photoluminescence (PL) spectrum. Monochromatic light from a xenon lamp is used as excitation source. PL spectrum shows two broad peaks, first near the band gap in UV (4.4-4.8eV) and another in the sub band gap region (< 4.0 eV). Band gap PL along with RRS peaks are reported for the first time. Photoluminescence excitation spectrum (PLE) shows a peak at 4.8 eV. Peak positions and full width at half maximum (FWHM) of RRS peaks depend upon the excitation energy. Dispersions of the fundamental and the third harmonic of the stretching mode of O-H with excitation energy are about 800 cm-1/eV and 2000 cm-1/eV respectively. This dispersion is much higher than reported in any other material.Comment: 20 page

Current Controller Based Power Management Strategy for Interfacing DG Units to Micro Grid

This paper proposes a power management strategy of parallel inveters based system, to enhance the power generation capacity of the existing system with distributed energy sources one has to choose DG source based inverter connected in parallel with the existing system.Two DG sources PV, Fuel cells feeds the DC voltage to two parallel inverters connected to the grid. Fixed band hysteresis current control with Instantaneous p-q power theory is adopted to create an artificial environment. Two parallel inverters are able to deliver the harvested power from PV, FC to grid and able to balance the load Without communication between parallel inverters this controller having the capability of load following, the harmonic components of currents at output of inverter are also very low; this will automatically reduces the circulating currents between parallel inverters. Simulation studies are carried out to investigate the results of PV, FC systems connected to the utility grid

Pattern of use of anti-hypertensive drugs amongst hypertensive patients in a tertiary care hospital: a cross sectional, observational study

Background: Hypertension is one of the primary modifiable risk factors for cardiac and renal diseases and is the single most important risk factor for stroke. Despite different guidelines for management of hypertension like Joint National Committee, British Hypertension Society, National Institute for Health and Care Excellence; there are still the clouds of controversy. The objective of the study was to evaluate the prescribing pattern of antihypertensive drugs among the patients attending medicine outpatient department of a tertiary care teaching hospitalMethods: A cross-sectional, observational study was conducted in our hospital over a period of six months. Relevant information was collected from medical records of 209 hypertensive patients fulfilling inclusion criteria. The collected data were sorted and analyzed.Results: Out of 209 patients, maximum were of age group of 45-65 years (55.02%). 115 (55.02%) were male and 94 (44.97%) were female. Diabetes mellitus (24.4%) was the most common associated disease with hypertension. Most of the patients had received single antihypertensive drugs (49.28%). Among the monotherapy category calcium channel blocker (82.78%) was the most commonly prescribed antihypertensive drug class followed by angiotensin receptor blocker (36.36%). Amlodipine (81.82%) was the most common among calcium channel blockers. The most frequent fixed drug combination prescribed consisted of amlodipine and atenolol. Most of the drugs were prescribed in generic name (90.9%).Conclusions: The treatment pattern, in general, conformed to standard treatment guidelines